$main-color:#36c;
$second-color:#37e;
$line-color:#32d;
$dark-color:#333;
* {
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}

body {
    background: url(https://images.pexels.com/photos/466685/pexels-photo-466685.jpeg?auto=compress&cs=tinysrgb&dpr=1&w=500) no-repeat center center/cover;
    min-height: 100vh;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    &::after {
        content: "";
        position: absolute;
        width: 100%;
        height: 100%;
        opacity: .5;
        left: 0;
        top: 0;
        background: $main-color;
        z-index: -1;
    }
    .card {
        width: 400px;
        padding: 2rem 3rem;
        background: #fff;
        h3 {
            font-weight: 400;
            color: $second-color;
            margin-bottom: 1rem;
        }
        form input {
            display: block;
            width: 100%;
            padding: 0.5rem;
            margin-bottom: 1rem;
            border: 1px solid $line-color;
            &:last-child {
                color: #fffeee;
                background: $second-color;
                transition: all .5s;
                &:hover {
                    background: $main-color;
                    color: #fff;
                }
            }
            &:focus {
                outline: 1px solid $main-color;
            }
        }
        ul {
            list-style: none;
            display: flex;
            justify-content: space-between;
            font-size: .9rem;
            li a {
                text-decoration: none;
                color: $dark-color;
                border-bottom: 1px solid transparent;
                transition: all .5s;
                &:hover {
                    color: $main-color;
                    border-bottom: 1px solid $main-color;
                }
            }
        }
    }
}